Draft hood for gas burners



p 14, 1954 J. w. MILLER 2,688,958

DRAFT HOOD FOR GAS BURNERS Filed July 10, 1950 2 Shee'ts-Sheet 1 IN V EN TOR.

John 14 M/Y/er Sept. 14, 1954 J. w. MILLER DRAFT HOOD FOR GAS BURNERS 2 Sheets-Sheet 2 Filed July 10 1950 INVENTOR. John W M/Y/er Patented Sept. 14, 1954 DRAFT HOOD FOR GAS BURNERS- John W. Miller, Lansing, Mich., assignor to Motor Wheel Corporation, Lansing, Mich., a corporation of Michigan Application July 10, 1950, Serial No. 172,801

11 Claims. 1

This invention relates to a draft hood and, more particularly, to a draft hood for gas burning heating devices.

It is an object of this invention to produce a draft hood of the type described which is economical to manufacture and which is constructed so that it may be connected more conveniently with a chimney flue.

More specifically, the invention contemplatesa draft hood in the form of a housing having a tubular baffle member mounted therein, the bafile member having an outlet fitting thereon projecting through an elongated slot in the wall of the housing so that the baffle maybe rotatably adjusted 'to a position wherein the outlet fitting is aligned with the chimney, thereby reducing the number of elbows required in the flue line connecting the draft hood with the chimney. The battle is arranged within the housing so that there will be zero draft on the outlet flues of the heating device.

In the drawings:

Fig. 1 is a plan view, partly in section, showing the draft hood arranged on a gas floor furnace and connected with a chimney.

Fig. 2 is a side elevation, partly in section, of the floor furnace with the draft hood of this invention arranged thereon.

Fig. 3 is a sectional view taken substantially along the lines 3--3 in Fig. 2.

Fig. 4 is a sectional view taken substantially along the lines 44 in Fig. 3.

Fig. 5 is a fragmentary elevational view of the draft hood with parts broken away to show the interior construction thereof.

Fig. 6 is a perspective View of the draft hood with the bafile removed therefrom.

Fig. '7 is a perspective view of the baffle.

The draft hood of this invention is designed to be used with gas burning heating devices which require zero draft. For the purpose of illustration, I have shown the draft hood, generally designated I0, used in conjunction with a gas floor furnace I I. A furnace of this type is usually supported within an opening in the floor of the structure being heated such as by the floor joists or headers I2. Furnace II is provided with an outer shell I3 within which there is disposed a heat exchanger I4 and a gas burner I5. The products of combustion from burner I5 flow through heat exchanger I-4 and out through a pair of flue out- The draft hood I0 is provided for connecting the flue outlets I6 of the furnace with a chimney I1 and, in the case of gas burning heating devices,

. 2 the hood is constructed such that there will be zero draft at the inlet of the draft hood. Draft hood It is preferably formed as a housing having aback wall it, a front wall I9 which is flanged at each end as at 20 for connection with back wall I 8, and a top wall 2 I. Back wall is is formed with a pair of inlet openings 22 which are spaced apart to correspond with the spacing of outlet flues I6 on furnace I I. A ferrule 23 surrounds each opening 22 and is arranged for connecting the interior of the draft hood with outlet flues It. The front wall I9 of the draft hood has an outwardly extending, semi-cylindrically shaped portion or bulge 24 which is centrally located relative to inlet openings 22. Wall portion 24 is provided with a horizontally extending elongated opening 25 which is spaced between the upper and lower edges of wall I 9.

Within the housing formed by walls I3, I9 and 2! (the bottom of the housing being open) there is positioned a tubular or cylindrical bafiie member 26 having its axis extending vertically within the housing. Bafile 2B is open at its top and bottom ends and is slidably nested in the semicylindrical wall portion 24. Bafiie 25 is dimensioned in diameter such as to slidably fit nicely between wall portion 24 and rear wall I8 as at 21. At one side the cylindrical baffle .26 is provided with an outlet opening 28 around which is arranged a tubular ferrule 29,. Ferrule 29 has a diameter corresponding to the height of opening 25 and, in turn, supports one side of baffle 2-6 in opening 25. The opposite side of baffle 26 is slidably supported by and between a pair of brackets 30 which are welded or otherwise affixed to the rear wall I8 of the housing. Brackets 3t engage the upper and lower edges of the cylindricalbaffie 26. Bafiie 26 is thus supported for rotative adjustment within the housing, the extent of rotative movement being limited by the length of the elongated opening 25. In the construction shown, bame 26 can be rotated through approximately the ferrule 29 being capable of being arranged in any angular position between the two extreme positions shown in Fig. 3 in broken lines.

Bolts 3| provide reinforcements extending between the front and back walls of the housing. The front wall I9 may be further reinforced by forming a circumferentially extending rib 32 around the semi-cylindrical wall portion 24.

Baffle 26 has a width greater than the diameter of inlet openings 22 and is arranged such that its upper and lower edges are disposed'above and below openings 22, respectively, withthe upper end of baffle 26 spaced below the top wall 21 of 3 casing I3 of the furnace.

In mounting the draft hood on the furnace, the hood is arranged with inlet ferrules 23 inserted within the outlet flues it of the furnace and, if necessary, brackets may be utilized for additionally supporting the draft hood on the After the draft hood is thus arranged on the furnace, ferrule 29 is rotated within opening 25 such as to be disposed in a convenient angular position for extending a flue pipe 34 between the draft hood and the chimney ll. It will be appreciated that the rotative adjustment of ferrule 29 permits the extension of flue 34 from the draft hood to the 3 chimney with a minimum of elbows.

In many localities the number of elbows permitted in the flue extension from the furnace to the chimney is limited by safety codes, and the use of the draft hood of this invention is, under such circumstances, especially advantageous.

It will be noted that the cylindrical baffle 26 forms an obstruction in the direct path between inlet openings 22 and outlet 28. The flue gases flowing from the burner are therefore caused to travel a circuitous path in flowing from inlets 22 to outlet 28.

must pass and the effect of the open bottom of the draft hood result in a substantially zero draft at the inlet of the draft hood. In case of a down draft in the chimney, the air flowing into the draft hood through opening 28 is reflected by baffle 26 and directed downwardly through the a the housing and with the lower end of the bafile j spaced above the open bottom 33 of the housing.

open bottom 23 ofthe housing. Bailie 26 bars any down draft entering the hood through opening 28 from flowing across the hood into openings 22 .and thus protects the burner from ex- 1 tinguishment by a down draft.

I claim:

1. A draft hood for a gas burning heating device comprising a housing having top and side walls and a substantially open bottom, said side wall having an inlet opening therein for the combustion products'from said gas heating device, and a tubular bafiie within said hood, said bafiie having an open end disposed within said housing and communicating directly with said open bottom of said housing, said tubular baffle having an outlet opening in its side wall, the side -wall of said baiile being spaced from said inlet opening and having a portion lying in-the direct path of travel between said inlet and said outlet openings whereby the side wall of said tubular baflie causes the gas flowing from said inlet opening to said outlet opening to travel a circuitous path to and through the open end of said tubular baifla'the side wall of said housing having a second opening therein of greater lateral extent than the outlet opening in the side wall of said baffle, said bafile being positioned in said housing with the portion of its side wall provided with said outlet opening adjacent the portion of means for connecting a smoke outlet duct with said outlet opening, and closure means on said housing closing said outlet opening of greater lateral extent except for the portion thereof which registers with the outlet opening on said baflie.

2. The combination set forth in claim 1 Wherein said baffle is a cylinder positioned vertically in said housing and open at the upper and lower ends thereof.

3. The combination set forth in claim 2 wherein said side wall portion of said housing provided with said second opening is of semi-cylindrical shape corresponding with the semi-cylindrical shape of said baffle, said bafile being disposed against the inner face of said cylindrical wall portion throughout the extent of said opening, the portion of said baffle which is not disposed against said cylindrical wall portion providing said wall in said chamber which prevents direct communication between said openings.

4. The combination set forth in claimv 2- wherein the upper edge of said baflie is spaced below the top Wallof said housing and the lower edge of said baflie is spaced above the lower edge of said housing.

5. The combination set forth in claim 4 wherein said inlet opening is disposed at a level between the upper and lower ends of said baflie.

6. A draft hood for a gas burning heating device comprising a housing open at its bottom side, and a tubular bafiie member within said housing having an end opening toward the bottom side of said housing, said) tubular baffle member having an outlet opening in the side wall thereof and being rotatable about its axis within said housing, said housing having an inlet opening in a side wall opposite said outlet opening, said inlet opening being located in said side wall at a point spaced from said open end of said baffle member whereby the wall of said tubular baffle member causes the gas flowing from said inlet to said outlet openings to travel a circuitous path to and through said open end of saidtubular bafile member, said housing being provided with an elongated opening in the side wall thereof spaced from said inlet opening, and an outlet fitting on said baffle member surrounding said outlet opening and extending through said elongated opening, said baffle member being rotatable in said housing to move said outlet fitting latterally through the extent of said elongated opening, and means movably mounted on the wall of said housing opening and closing said elongated opening except for the portion thereinlet and outlet of through which said outlet fitting extends.

7. The combination set forth in claim 6 wherein said baffle member is cylindrical in shape, the wall portion of said housing provided with said elongated opening being arcuate in shape to correspond with the cylindrical surface of said baffle member, said baffle member being supported against said arcuate wall portion with the cylindrical'wall thereof providing said means closing said elongated opening except for the portion thereof through which said outlet fitting extends.

8. A draft hood as called for in claim 6 wherein a portion of the side wall of said baffle is disposed adjaoent the portion of said housing provided with said elongated opening and forms said closure means.

9. A draft hood for a gas burning heating device comprising a housing having top and side walls and asubstantially open bottom, said side wall having an inlet opening therein for the combustion products from said gas burning heating device, a tubular baffle positioned vertically within said hood and having an outlet opening in its side wall, said bathe-having a lower open end which is disposed in a plane above said open bottom and below said inlet opening, the side wall of said bafile being spaced from said inlet opening and extending vertically to above and below said inlet opening so .as to lie in the direct path of travel between said inlet and outlet openings whereby the side wall of said baflle causes the gas flowing from said inlet to said outlet opening to travel a circuitous path to and through the open end of said tubular baflle, duct means connected with said outlet opening and extending to a point exteriorly of said housing, said last mentioned means being adapted for connection with a smoke outlet duct, and means in said housing supporting said baflle for rotation on a vertical axis to vary the angular position of said outlet opening and the duct means connected therewith relative to said housing.

10. A draft hood as called for in claim 9 wherein the side wall of said housing is provided with a second opening of greater lateral extent than the outlet opening in said banle, said duct means extending through said second opening, and the side wall of said bafile closing said opening of greater lateral extent except for the portion thru which said duct means extends.

11. The combination called for in claim 10 wherein said duct means slidably engages the lower edge of said second opening to support one side of said bafile in said housing, and means on a wall of said housing opposite said opening of greater lateral extent engaging said baffle for supporting the opposite side of said bafile.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,891,600 Lancaster Dec. 20, 1932 2,222,663 Handley Nov. 26. 1940 2,257,240 Livar Sept. 30, 1941 2,486,780 Fenberg Nov. 1, 1949 FOREIGN PATENTS Number Country Date 132,716 Great Britain Sent. 25, 1919 

